ref: e662a9500f826a7f534170e981da4987ca8d83f3
dir: /src/base/ftadvanc.c/
/**************************************************************************** * * ftadvanc.c * * Quick computation of advance widths (body). * * Copyright (C) 2008-2021 by * David Turner, Robert Wilhelm, and Werner Lemberg. * * This file is part of the FreeType project, and may only be used, * modified, and distributed under the terms of the FreeType project * license, LICENSE.TXT. By continuing to use, modify, or distribute * this file you indicate that you have read the license and * understand and accept it fully. * */ #include <freetype/internal/ftdebug.h> #include <freetype/ftadvanc.h> #include <freetype/internal/ftobjs.h> static FT_Error _ft_face_scale_advances( FT_Face face, FT_Fixed* advances, FT_UInt count, FT_Int32 flags ) { FT_Fixed scale; FT_UInt nn; if ( flags & FT_LOAD_NO_SCALE ) return FT_Err_Ok; if ( !face->size ) return FT_THROW( Invalid_Size_Handle ); if ( flags & FT_LOAD_VERTICAL_LAYOUT ) scale = face->size->metrics.y_scale; else scale = face->size->metrics.x_scale; /* this must be the same scaling as to get linear{Hori,Vert}Advance */ /* (see `FT_Load_Glyph' implementation in src/base/ftobjs.c) */ for ( nn = 0; nn < count; nn++ ) advances[nn] = FT_MulDiv( advances[nn], scale, 64 ); return FT_Err_Ok; } /* at the moment, we can perform fast advance retrieval only in */ /* the following cases: */ /* */ /* - unscaled load */ /* - unhinted load */ /* - light-hinted load */ /* - if a variations font, it must have an `HVAR' or `VVAR' */ /* table (thus the old MM or GX fonts don't qualify; this */ /* gets checked by the driver-specific functions) */ #define LOAD_ADVANCE_FAST_CHECK( face, flags ) \ ( flags & ( FT_LOAD_NO_SCALE | FT_LOAD_NO_HINTING ) || \ FT_LOAD_TARGET_MODE( flags ) == FT_RENDER_MODE_LIGHT ) /* documentation is in ftadvanc.h */ FT_EXPORT_DEF( FT_Error ) FT_Get_Advance( FT_Face face, FT_UInt gindex, FT_Int32 flags, FT_Fixed *padvance ) { FT_Face_GetAdvancesFunc func; if ( !face ) return FT_THROW( Invalid_Face_Handle ); if ( !padvance ) return FT_THROW( Invalid_Argument ); if ( gindex >= (FT_UInt)face->num_glyphs ) return FT_THROW( Invalid_Glyph_Index ); func = face->driver->clazz->get_advances; if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) { FT_Error error; error = func( face, gindex, 1, flags, padvance ); if ( !error ) return _ft_face_scale_advances( face, padvance, 1, flags ); if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) return error; } return FT_Get_Advances( face, gindex, 1, flags, padvance ); } /* documentation is in ftadvanc.h */ FT_EXPORT_DEF( FT_Error ) FT_Get_Advances( FT_Face face, FT_UInt start, FT_UInt count, FT_Int32 flags, FT_Fixed *padvances ) { FT_Error error = FT_Err_Ok; FT_Face_GetAdvancesFunc func; FT_UInt num, end, nn; FT_Int factor; if ( !face ) return FT_THROW( Invalid_Face_Handle ); if ( !padvances ) return FT_THROW( Invalid_Argument ); num = (FT_UInt)face->num_glyphs; end = start + count; if ( start >= num || end < start || end > num ) return FT_THROW( Invalid_Glyph_Index ); if ( count == 0 ) return FT_Err_Ok; func = face->driver->clazz->get_advances; if ( func && LOAD_ADVANCE_FAST_CHECK( face, flags ) ) { error = func( face, start, count, flags, padvances ); if ( !error ) return _ft_face_scale_advances( face, padvances, count, flags ); if ( FT_ERR_NEQ( error, Unimplemented_Feature ) ) return error; } error = FT_Err_Ok; if ( flags & FT_ADVANCE_FLAG_FAST_ONLY ) return FT_THROW( Unimplemented_Feature ); flags |= (FT_UInt32)FT_LOAD_ADVANCE_ONLY; factor = ( flags & FT_LOAD_NO_SCALE ) ? 1 : 1024; for ( nn = 0; nn < count; nn++ ) { error = FT_Load_Glyph( face, start + nn, flags ); if ( error ) break; /* scale from 26.6 to 16.16, unless NO_SCALE was requested */ padvances[nn] = ( flags & FT_LOAD_VERTICAL_LAYOUT ) ? face->glyph->advance.y * factor : face->glyph->advance.x * factor; } return error; } /* END */